Cervical and Breast Cancers: Killers On The Prowl

A week before the United Nations (UN) Summit on Non-Communicable Diseases (NCDs) opens, reviewing outcomes of a new global analysis on breast and cervical cancers is warranted. In developing nations, breast and cervical cancers are rapidly replacing complications from pregnancy and childbirth as the leading causes of death in women below 50 years of age. In the Middle East and North Africa, nearly 40% of all breast cancer deaths are in women of reproductive age, compared to 10% in Europe. In countries such as Bangladesh, the fraction can be higher than 50%. India has a population of 366.58 million women aged 15 years and older who are at risk of developing cervical cancer.
According to a new global analysis by the Institute for Health Metrics and Evaluation (IHME) at the University of Washington, the burden of breast and cervical cancers is shifting from the developed to the developing countries. The new study, ‘Breast and cervical cancer trends for 187 countries, 1980-2010: a systematic analysis’ is published in The Lancet. Coinciding with the study’s release, IHME has published a report, 'The Challenge Ahead: Progress and setbacks in breast and cervical cancer, which provides global, regional, and country data for cases, deaths, and risks over the past three decades'. This is the first time there has been a comprehensive time series of cancer risks worldwide, with the focus on to raise awareness about the problem overall.

According to this report, in 1980, 65% of all breast cancer cases were in developed countries. But by 2010, more than 50% of the cases occurred in developing countries, some of which saw an annual rise of more than 7.5%, which is more than twice the global rate. The risk of cervical cancer is also much higher in developing countries, with 76% of new cervical cancer cases occurring in developing regions. Sub-Saharan Africa alone accounted for 22% of all cervical cancer cases in 2010.

A 2010 WHO report cites cervical cancer as the most frequent cancer among women in India, between 15 and 44 years of age. Current estimates indicate that every year 134,420 Indian women are diagnosed with cervical cancer and 72825 die from the disease. About 7.9% of women in the general population are estimated to harbour cervical HPV infection at a given time, and 82.5% of invasive cervical cancers are attributed to HPVs 16 or 18. The incidence of breast cancer is also rising in India and is now the second most commonly diagnosed cancer in women after cervical cancer. It is estimated that in 2008 there were 115251 new cases of breast cancer which are likely to reach almost 200000 per year by 2030. Data from National Cancer Registry Programme shows that in urban areas of India breast cancer has now surpassed cervical cancer as the most frequently diagnosed cancer in women, with the average age of presentation being around 40 years--10 years younger as compared to the developed world.

“Women in high-income countries like the United States and the United Kingdom are benefiting from early cancer screenings, drug therapies, and vaccines,” said Dr. Rafael Lozano, Professor of Global Health at IHME and one of the co-authors of the Lancet study, “We are seeing the burden of breast and cervical cancer shifting to low-income countries in Africa and Asia. This is the one of the early signs of the emerging threat of non communicable diseases in these countries.”

According to Dr.Lozano there are two main challenges in combating breast and cervical cancer:

(i) The first is the challenge of awareness. There should be strong campaigns to promote safe sex practices and breast feeding. Women need to know that the main cause of cervical cancer is the Human Papilloma Virus (HPV), which is transmitted through sexual contact, and that breast feeding not only improves the child’s immunity from childhood diseases, but also lowers the mother’s risk of breast cancer later in life. Apart from reducing the risk factors, timely screening can catch the cancers early and raise their chances of survival.

(ii) The second challenge is of availability of early screening, treatment and care. Mammography equipments to detect breast cancer are costly. It also costs money to train technicians to accurately read mammograms. The vaccines to prevent infection with the HPV virus are expensive too. But if countries like Peru and Yemen can make these vaccines available to their women on a priority basis, then so can other countries, including India.

Another preventable risk factor for breast cancer, according to Dr Lozano, is obesity. He cites the example of Mexico, where the risk of incidence of breast cancer has doubled since 1980, with two-thirds of the Mexican women being overweight and one quarter of them obese. Brazil also has an obesity epidemic and there the risk of incidence has gone up but the risk of death from breast cancer has remained flat.

While HPV is a necessary cause of cervical cancer, other cofactors which have been established as necessary for progression from cervical HPV infection to cancer are tobacco smoking, long-term hormonal contraceptive use, and co-infection with HIV. Well-organized cervical screening programs or widespread good quality cytology can reduce cervical cancer incidence and mortality. Women in low income populations are at an increased risk of cervical cancer as they have less education about safe sex practices and poor access to health services. If not detected in early stages, cervical cancer can become invasive and spread quickly.

Dr Lozano feels that improvements in treatment, increased access to treatment and early detection decrease the risk of mortality from breast cancers, as is happening in the US and UK, and even in South Africa, although Rwanda remains an aberration with the risk increasing from 1% to 1.7%.

Even within some regions the trends have be found to be very different. Women in Peru have half the risk today of dying from breast cancer than they had in 1980, while the risk has remained nearly the same over this period in nearby Argentina. In China, women had a 1 in 133 risk of dying from cervical cancer in 1980 and now have a risk of 1 in 342, one of the lowest in the world. Over the same period, Thailand’s risk stayed at about 1 in 100.

“The fact that similar countries with similar populations have very different trends tells us that all the usual suspects – diet, genetics, obesity – are only part of the picture,” said Dr. Christopher Murray, IHME Director and one of the paper’s co-authors. “This is why it is critical to build the evidence base in this area, through expanded cancer registries and use of new techniques, such as verbal autopsies, to gather data. Then we will be able to answer why the progress we are seeing in some countries is not shared elsewhere.”

Shobha Shukla - CNS(The author is the Managing Editor of Citizen News Service (CNS). She is a J2J Fellow of National Press Foundation (NPF) USA. She has worked earlier with State Planning Institute, UP and taught physics at India's prestigious Loreto Convent. Email: shobha@citizen-news.org, website: http://www.citizen-news.org)